Opera loudspeakers Callas

Product Description

The Callas is small-medium sized speaker. The internal volume is 14 liters dedicated to the woofer. The cabinet is made from MDF and veneered curved plywood . The thickness ranging from 25 mm (sides) to 50 mm of the front panel . The front panel on the inner side, in correspondence of the holes of the woofer, is milled so that turbulence does not arise in the vicinity of the speaker membranes.

Internal sides are non parallel. One of the problems of speakers are the resonances of the cabinet and the other is internal reflections Regarding the rigidity this is guaranteed by the thickness and the weight of the walls. In order to reduce internal reflections behind the woofers there are two layers of absorbent material with pyramidal profile for a total thickness of 20 centimeters.

The absorbing material is an open cell polyurethane foam with pyramidal profile ( with base 7 x 7 cm , 3 cm and 7 cm for the basic height of the pyramid ) . This porous material , with its particular profile , provides an absorbing coefficient of 60% at 250 Hz and reaches almost 100% at 500 Hz. Strategically placing the right amount of this absorbent material inside the cabinet befall both reflections ( which would produce masking ) and the normal modes of the cavity which would produce annoying noise .

Woofers are made by Seas on Opera specifications . It is an 7″ woofer with re-cooked polypropylene cone and rubber rim with copper ring above and bellow the T-shaped pole piece and 12 mm pk-pk displacement. (a Seas technology named Excel ). This component , although used with a cutoff at 2000 Hz is able to work perfectly up to 5000 Hz . This guarantees a perfect overlap between the woofer and tweeter two octaves

before and beyond the cutoff frequency . With musical program the Callas con easily produce more than 100 SPL in the listener position with very low distortion.

The diaphragm of the midrange is made with re-coked polypropylene (annealed) . The polypropylene has a good internal damping but a low stiffness. Subjecting it to an heat stress it acquires rigidity without losing too much internal damping . The annealing, however, is a delicate process . Scanspeak 9700 tweeter needs no introduction: it is one of the best tweeters ever made and , in some respects , is still unsurpassed . Currently, this tweeter is used on models Malibran , Caruso, Tebaldi , Callas Grand , 2014, Callas in 2014 and also on the new Opera Quinta 2014. Besides the quality of sound, this tweeter is also highly reliable.